System for damping engine speed oscillations

Claim 3

The system of claim 1 wherein said electric machine is a starter/alternator.

Claim 4

The system of claim 1 wherein said controller is further effective to process said first signal by use of an inverse notch filter, and is effective to attenuate said crankshaft oscillations at a certain frequency value determined by said inverse notch filter.

Claim 5

The system of claim 1 wherein said controller is further effective to implement said inverse notch filter by use of a zero-order hold approximation.

Claim 6

The system of claim 1 wherein said controller is further effective to implement said inverse notch filter by use of a Tustin approximation.

Claim 7

The system of claim 1 wherein said system has a phase margin and wherein said controller is further effective to process said first signal by use of a lead compensator, effective to improve said phase margin.

Claim 8

The system of claim 3 wherein said controller is further effective to partition said first signal into a dc component and an ac component prior to using said inverse notch filter.

Claim 9

The system of claim 1 wherein said controller is further effective to limit said second signal to a predetermined range of values.

Claim 10

The system of claim 1 wherein said vehicle is a hybrid electric vehicle.

Claim 11

A hybrid electric vehicle having improved damping of engine crankshaft speed oscillations and comprising: an engine which drivably rotates a crankshaft at a first speed which includes certain oscillations; a starter/alternator which is operatively coupled to said crankshaft, and which is effective to selectively provide torque to said crankshaft; a sensor which measures said first speed and which generates a first signal based upon said measured first speed; and a controller which is communicatively coupled to said sensor and to said starter/alternator, said controller being effective to receive said first signal, to partition said first signal into a second signal and a third signal, to filter said second signal and said third signal by use of an inverse notch filter, and to communicate a torque command signal to said starter/alternator based upon said filtered second and third signals, said torque command signal being effective to cause said starter/alternator to selectively provide torque to said crankshaft, thereby substantially damping said certain oscillations in said first speed.

Claim 12

A hybrid electric vehicle having improved damping of engine crankshaft speed oscillations and comprising: an engine which drivably rotates a crankshaft at a first speed which includes certain oscillations; a starter/alternator which is operatively coupled to said crankshaft, and which is effective to selectively provide torque to said crankshaft; a sensor which measures said first speed and which generates a first signal based upon said measured first speed; and a controller which is communicatively coupled to said sensor and to said starter/alternator, said controller being effective to receive said first signal, to partition said first signal into a second signal and a third signal, to filter said second signal and said third signal by use of an inverse notch filter, and to communicate a torque command signal to said starter/alternator based upon said filtered second and third signals, said torque command signal being effective to cause said starter/alternator to selectively provide torque to said crankshaft, thereby substantially damping said certain oscillations in said first speed.

Claim 13

The hybrid electric vehicle of claim 10 wherein said controller has a certain phase margin and wherein said controller is further effective to process said torque command signal by use of a lead compensator, thereby improving said phase margin.

Claim 14

The hybrid electric vehicle of claim 10 wherein said controller is further effective to process said torque command signal by use of a limiting function.

Claim 15

The hybrid electric vehicle of claim 10 wherein said torque command signal includes an ac component and a dc component, and wherein said controller is further effective to process said torque command signal by use of a high pass filter, thereby removing said dc component prior to communicating said torque command signal to said starter/alternator.

Claim 18

The method of claim 14 wherein said supplemental torque source comprises a starter/alternator.

Claim 19

The method or claim 14 further comprising the steps of: processing said second signal by use of a variable lead compensator, effective to generate a third signal; and utilizing said third signal to generate said output signal.

Claim 20

The method of claim 16 further comprising the steps of: processing said third signal by use of a limiting circuit, effective to generate a fourth signal; and utilizing said fourth signal to generate said output signal.

Claim 21

The method of claim 17 wherein said fourth signal includes a dc component and an ac component, said method further comprising the steps of: processing said fourth signal by use of a high pass filter effective to remove said dc component and to generate said output signal.